Question 1: Define adrenaline and describe its main function in the human body.

Answer: Adrenaline is a hormone released by the adrenal glands that prepares the body for 'fight or flight' responses by increasing heart rate, blood flow, and energy availability.

Question 2: Explain how thyroxine influences metabolic rate and growth.

Answer: Thyroxine increases the metabolic rate by stimulating enzyme activity, which helps regulate energy use and promotes growth and development.

Question 3: Describe the mechanism by which adrenaline triggers a response in target cells.

Answer: Adrenaline binds to specific receptors on target cells, activating a cascade of enzyme reactions that lead to the physiological responses such as increased heart rate.

Question 1: A person’s blood adrenaline concentration increases from 50 ng/mL to 150 ng/mL during stress. Calculate the percentage increase in adrenaline levels.

Answer: Percentage increase = [(150 - 50) / 50] × 100 = 200%

Question 2: If a thyroid gland secretes 80 micrograms of thyroxine daily, how many milligrams is this?

Answer: 0.08 milligrams

Question 1: Describe a simple experiment to measure the effect of thyroxine on metabolic rate in laboratory animals. Include variables and safety precautions.

Answer: An experiment could involve administering different doses of thyroxine to groups of animals and measuring the oxygen consumption rate. Independent variable: dose of thyroxine; dependent variable: metabolic rate. Control variables include age, species, and environment. Safety precautions include handling hormones with gloves, proper disposal of biological waste, and ensuring ethical treatment of animals.

Question 1: A study reports that individuals with hyperthyroidism have an average basal metabolic rate (BMR) 20% higher than healthy individuals. Explain how excess thyroxine could cause this increase.

Answer: Excess thyroxine raises the metabolic activity of cells, leading to increased energy consumption and higher BMR in hyperthyroid individuals.

Question 2: Discuss how understanding adrenaline's role can aid in developing treatments for allergic reactions.

Answer: Understanding adrenaline’s role in constricting blood vessels and relaxing airway muscles helps in formulating adrenaline auto-injectors to rapidly counteract severe allergic reactions (anaphylaxis), restoring blood pressure and breathing.

Question 1: Explain how synthetic adrenaline is used in medical emergencies and discuss potential side effects.

Answer: Synthetic adrenaline is used in emergency treatment of cardiac arrest and severe allergic reactions to quickly increase heart rate and constrict blood vessels. Side effects may include increased blood pressure, rapid heartbeat, anxiety, and tremors if not administered properly.

Question 2: Describe how advances in biotechnology could improve the production of thyroxine for medical use.

Answer: Biotechnology can enable the production of synthetic thyroxine using genetically engineered bacteria or yeast, ensuring a consistent and pure supply. This reduces reliance on animal sources and allows for precise dosage formulations.